Can I run gpt-oss-120b on the Apple M4?
Won't runMXFP4 needs 64.3 GB, 41.9 GB more than the 22.4 GB of usable memory, and no tracked quant runs at a usable speed with 32 GB of RAM.
32 GB unified memory · 120.0 GB/s · FP16 8.5 TFLOPS. Assumes 8k context and an f16 KV cache. Verdicts are shown for each memory size.
Verdict by memory size
The page uses the 32 GB configuration; here is every size.
- 16 GBWon't run
- 24 GBWon't run
- 32 GBWon't run
Every quant of gpt-oss-120b on the Apple M4
| Quant | File size | Verdict | Speed | Memory | Runs as | Notes |
|---|---|---|---|---|---|---|
| MXFP4baseline | 63.39 GB | Won't run | — | Needs about 64.3 GB; 28.0 GB of memory is free (22.4 GB usable by the GPU) | — | — |
Reasoning models spend extra tokens thinking, so their speed thresholds are 1.5× stricter (30 / 12 / 3 tok/s).
Where the memory goes at MXFP4
MXFP4 does not fit — it needs 64.3 GB against 22.4 GB of usable memory, so there is nothing to break down.
Context length vs. KV cache
| Context | KV f16 | KV q8_0 | KV q4_0 |
|---|---|---|---|
| 4k | 64.1 GBdoes not fit | 64.0 GBdoes not fit | 64.0 GBdoes not fit |
| 8k | 64.3 GBdoes not fit | 64.1 GBdoes not fit | 64.1 GBdoes not fit |
| 16k | 64.6 GBdoes not fit | 64.4 GBdoes not fit | 64.2 GBdoes not fit |
| 32k | 65.4 GBdoes not fit | 64.8 GBdoes not fit | 64.5 GBdoes not fit |
| 64k | 66.9 GBdoes not fit | 65.8 GBdoes not fit | 65.2 GBdoes not fit |
| 128k | 69.9 GBdoes not fit | 67.7 GBdoes not fit | 66.5 GBdoes not fit |
S = Runs great · A = Runs well · B = Runs slowly · F = Won't run
At MXFP4 no context length fits: even 4k needs 64.1 GB against 22.4 GB.
Estimated speed
- Generation
- —
- Prompt processing
- Prompt-processing estimates only apply when the whole model runs on the GPU.
Measured on this exact combination
No public measurement for this exact combination yet; the numbers above are estimates.
If this is not enough
A smaller model that runs well on the Apple M4
Runs wellQwen3 30B-A3B (2507): Runs well, est. 12.8 tok/s (10.2–15.4, calibrated estimate ±20%)
gpt-oss-120b on the Apple M4 Max (40-core GPU)
Runs greatMXFP4: Runs great, est. 53.4 tok/s (42.7–64.0, calibrated estimate ±20%)
How to run it
No run command: this file does not fit in the 22.4 GB of unified memory the GPU can use.
Related pages
Guide: Running local LLMs on a Mac (M4, M5): how much unified memory?
Other models on the Apple M4
gpt-oss-120b on other hardware
Frequently asked questions
Can I run gpt-oss-120b on the Apple M4?
MXFP4 needs 64.3 GB, 41.9 GB more than the 22.4 GB of usable memory, and no tracked quant runs at a usable speed with 32 GB of RAM. MXFP4 needs 64.3 GB at 8k context; the GPU can use 22.4 GB of the unified memory.
How much context can gpt-oss-120b use on the Apple M4?
No context length fits: even at 4k, MXFP4 needs 64.1 GB against 22.4 GB of usable memory.
Which quant should I use, and how fast is it?
No tracked quant runs here: the smallest file (MXFP4, 63.39 GB) needs 64.3 GB at 8k context, and the GPU can use 22.4 GB of the unified memory.
Speeds are estimates from memory bandwidth, calibrated against public benchmarks, and each one comes with an error band and a confidence label. Real results vary with drivers, backend, context length and thermals.